Domestic vs. Irrigation Wells in Idaho: What Acreage Homeowners Need to Know

Owning property with acreage in the Treasure Valley often raises questions about wells. Can you have more than one? What’s the difference between a domestic well and an irrigation well? And how do water rights factor in?

At Hydro, we hear these questions every week. Here’s a guide based on Idaho Department of Water Resources (IDWR) statutes to help homeowners navigate the rules.

What is a “domestic” well in Idaho?

Under Idaho Code (Idaho Code §42-111), a domestic well supplies water for:

• Homes (up to 13,000 gallons per day for in-house and outside use)

• Small-scale irrigation (up to ½ acre of lawn or garden)

• Livestock watering

Domestic wells are exempt from the state’s typical water-right permitting process. You don’t need a formal water right to drill and use one, as long as your use stays within the “domestic exemption” limits.

What if I want to water more than ½ acre?

That’s where irrigation wells come in.

• To irrigate more than ½ acre, you need a separate water right from IDWR.

• An irrigation right specifies how much land can be irrigated, how much water can be pumped, and what priority date your right carries.

• Without a permitted water right, you cannot legally pump water from a well to irrigate beyond the ½ acre domestic exemption.

Can I have multiple wells on my property?

Yes—but with conditions:

1. Multiple domestic wells?

   
   

   • In most cases, IDWR only allows one domestic well per parcel under the exemption.

   • A second domestic well typically requires a special showing of necessity or approval from IDWR.

   
   

2. Domestic + irrigation wells?

   
   

   • This is common for acreage properties.

   • Your house may be served by a domestic well, while a separate irrigation well (with a valid water right) supplies fields, pastures, or larger landscaped areas.

   
   

3. Shared wells?

   
   

   • Two or more homes may share a single domestic well, but the total use must still fall under the domestic exemption, or a water right is required.

   
   

How do irrigation rights work?

Idaho follows the doctrine of prior appropriation: “first in time, first in right.”

• Each irrigation right has a priority date—the earlier the date, the stronger the right during times of shortage.

• Rights are tied to specific land and must be used on that land. You can’t just transfer irrigation water to a new field without IDWR approval.

• If you don’t use an irrigation right for five consecutive years, it may be subject to forfeiture.

What about changes or drilling a new well?

Any new irrigation well requires an approved water right and a drilling permit from IDWR. The driller files a notice with the Department, and once the well is complete, you’ll need to follow through on licensing and reporting.

If you’re considering drilling an additional well (domestic or irrigation), it’s smart to first:

• Check your property’s existing water rights,

• Confirm whether you’re in a Ground Water Management Area (GWMA) or Critical Ground Water Area (CGWA) where extra restrictions apply,

• Work with a licensed driller (like Hydro) who understands Treasure Valley groundwater conditions and IDWR requirements.

Common Homeowner Questions

Q: Can I water my pasture with my domestic well?

A: Only up to ½ acre. Beyond that, you need an irrigation right.

Q: What if I drill a second well without a water right?

A: It may be ordered shut down by IDWR. Always secure the proper permits and rights first.

Q: My neighbor has both a domestic and irrigation well. Can I do the same?

A: Yes, if your property has irrigation rights and you follow IDWR rules.

Q: How do I know if my property has irrigation rights?

A: Check your deed, irrigation district records, or use IDWR’s Water Rights online search tool.

Why this matters in the Treasure Valley

With rapid growth and changing irrigation practices, groundwater in parts of Ada and Canyon Counties is under stress. That’s why IDWR closely regulates well spacing, water rights, and multiple wells per parcel.

Following the rules isn’t just about compliance—it’s about protecting your water supply and your neighbors’ wells for the long term.

Hydro: Helping Acreage Owners Do It Right

Whether you’re drilling a new well, decommissioning an old one, or sorting out water rights, Hydro is the Treasure Valley’s specialist in domestic and irrigation wells. We’ll help you:

• File permits with IDWR,

• Stay compliant with domestic exemption limits,

• Understand your irrigation rights,

• Drill, abandon, or maintain wells correctly.

Bottom line: A domestic well covers your home and a little yard irrigation. Anything beyond that requires irrigation rights and, often, a separate irrigation well. Hydro can guide you through the process and keep your property in compliance with Idaho water law.

-Jenae Sexton, owner of Hydro Drilling